In 1969, 9.1 percent of all clinical dental restorations placed in the United States consisted of crowns, inlays or bridgework, and the dental profession consumed 44 percent of the entire domestic production of gold. Now that the price of gold has been cut loose from Treasury support, the cost of the metal has risen significantly. The availability of a dental casting alloy with low precious metal content would free the dental profession from dependence on the volatile and uncertain future price and availability of gold. This research is intended to develop an alloy formulation low in precious metal content for use in routine fixed prosthodontic (crown and bridge) procedures. Presently used dental casting gold alloys have moderate elastic moduli and resistance to permanent deformation. The development of a dental casting alloy with both a higher yield strength and modulus of elasticity would enable restorations to be made substantially thinner and less bulky, given the same loading forces. Less tooth structure need then be sacrificed, and bending of the long span prostheses would be minimized by increasing the modulus and yield strength of the metals, while retaining the excellent ductility, corrosion resistance, low casting temperatures, and other handling properties of the presently used gold alloys. A program for the development and evaluation of high strength, high modulus copper-nickel-manganese-gold-silver casting alloys for dental applications will be undertaken. Alloys wll be formulated, tested for mechanical properties, handling characteristics, electrochemical corrosion, and in vivo behavior when fabricated into full crowns in experimental animals.